'''' This code is part of Document Solutions for Imaging demos.'' Copyright (c) MESCIUS inc. All rights reserved.''Imports SystemImports System.IOImports System.DrawingImports System.Collections.GenericImports System.LinqImports GrapeCity.Documents.DrawingImports GrapeCity.Documents.TextImports GrapeCity.Documents.ImagingImports GCTEXT = GrapeCity.Documents.Text
'' This sample shows the results of enlarging a small (57 by 57 pixels) image'' of a QRCode using the 4 available interpolation modes.'' While for most images (such as portraits or landscapes), Linear or Cubic'' interpolation modes would normally yield better-looking results,'' for images like QRCodes or barcodes using the NearestNeighbor or'' Downscale modes is more appropriate.'''' See EnlargeImage for an example where a small photo (portrait of a woman)'' is enlarged using the same 4 interpolation modes.Public Class EnlargeQRCode    Public Function GenerateImage(            ByVal pixelSize As Size,            ByVal dpi As Single,            ByVal opaque As Boolean,            Optional ByVal sampleParams As String() = Nothing) As GcBitmap
        '' Create and clear the target bitmap:        Dim targetBmp = New GcBitmap(pixelSize.Width, pixelSize.Height, opaque, dpi, dpi)        targetBmp.Clear(Color.Transparent)
        Const fontSize As Integer = 16        Dim xpad As Integer = CInt(dpi * 0.5F)        Dim ypad As Integer = CInt(dpi * 0.7F)        Dim tf As New TextFormat() With {            .Font = GCTEXT.Font.FromFile(Path.Combine("Resources", "Fonts", "FreeSerif.ttf")),            .FontSize = fontSize        }
        '' Small image of a QRCode:        Using origBmp As New GcBitmap()            Using stm = File.OpenRead(Path.Combine("Resources", "ImagesBis", "QRCode-57x57.png"))                origBmp.Load(stm)            End Using
            '' Make sure opaqueness of the original bitmap matches the target:            origBmp.Opaque = targetBmp.Opaque
            Dim ip As New Point(xpad, ypad)
            '' Draw the original with the original size:            targetBmp.BitBlt(origBmp, ip.X, ip.Y)            Using g = targetBmp.CreateGraphics(Nothing)                g.DrawString($"⟵ Original image ({origBmp.PixelWidth} by {origBmp.PixelHeight} pixels)",                             tf,                             New PointF(xpad * 2 + origBmp.Width, ip.Y))            End Using            ip.Y += origBmp.PixelHeight + ypad
            '' We are going to enlarge the original small image by a factor of 6:            Dim f As Integer = 6            Dim twidth As Integer = origBmp.PixelWidth * f            Dim theight As Integer = origBmp.PixelHeight * f
            '' Enlarge and draw 4 copies of the image using the 4 available interpolation modes:            Using bmp = origBmp.Resize(twidth, theight, InterpolationMode.NearestNeighbor)                targetBmp.BitBlt(bmp, ip.X, ip.Y)            End Using            drawCaption(targetBmp, tf, "InterpolationMode.NearestNeighbor", ip.X, ip.Y + theight)
            Using bmp = origBmp.Resize(twidth, theight, InterpolationMode.Cubic)                targetBmp.BitBlt(bmp, ip.X + twidth + xpad, ip.Y)            End Using            drawCaption(targetBmp, tf, "InterpolationMode.Cubic", ip.X + twidth + xpad, ip.Y + theight)
            ip.Y += theight + ypad
            Using bmp = origBmp.Resize(twidth, theight, InterpolationMode.Linear)                targetBmp.BitBlt(bmp, ip.X, ip.Y)            End Using            drawCaption(targetBmp, tf, "InterpolationMode.Linear", ip.X, ip.Y + theight)
            Using bmp = origBmp.Resize(twidth, theight, InterpolationMode.Downscale)                targetBmp.BitBlt(bmp, ip.X + twidth + xpad, ip.Y)            End Using            drawCaption(targetBmp, tf, "InterpolationMode.Downscale", ip.X + twidth + xpad, ip.Y + theight)        End Using        Return targetBmp    End Function
    '' Local helper to draw captions:    Sub drawCaption(ByRef targetBmp As GcBitmap, ByRef tf As TextFormat, ByVal caption As String, ByVal x As Single, ByVal y As Single)        Using g = targetBmp.CreateGraphics(Nothing)            g.DrawString(caption, tf, New PointF(x, y))        End Using    End SubEnd Class